WHAT'S UP DOC? Community-Acquired Pneumonia

Q: My mom is pretty independent and lives alone, but somehow she developed pneumonia. Why does this happen?

A: Pneumonia is an infection (or less commonly an inflammation) of the lungs that causes symptoms such as fever, chills, chest pain, cough, malaise and/or shortness of breath, although nausea/vomiting, mental status changes and many other symptoms are possible as well. Prior to 1936 pneumonia was the number one cause of death in the United States, but the advent of antibiotics has improved on this. There are still around 5 million cases of pneumonia each year in the United States resulting in over 60,000 deaths, making pneumonia (combined with influenza) the eighth leading cause of death.

The lungs are frequently exposed to small amounts of bacteria, viruses and/or particulate material that are aspirated (breathed in) from the upper airway (micro-aspirations, as opposed to the much less common large aspirations such as in a patient whose gag reflex is compromised or from some other pathogenic occurrence). The defenses of the lungs usually clear these micro-aspirations, and no pneumonia occurs. However, in some cases the defense mechanisms are overwhelmed, either because the pathogen is particularly virulent or because of a weakness or defect (even if it is temporary) in the lung’s defenses.

Although pneumonia can be acquired by people in the hospital (HAP or hospital acquired pneumonia, such acquired by someone on a ventilator or as a complication of another condition or procedure) or as healthcare-associated pneumonia (HCAP, such as acquired in a nursing home or rehab center), by far the most common way people get pneumonia is community-acquired pneumonia (CAP). Many things may increase the risk of a patient developing CAP, including a history of certain concomitant illnesses (for example COPD, immune compromised states, alcoholism, other lung diseases, kidney diseases, malnutrition, diabetes, others), advancing age (specifically being over age 65), smoking, certain medications (for example some stomach acid reducing medications, certain antipsychotic medications, others) or other factors.

CAP can be caused by many different infectious agents including bacteria, mycoplasma, viruses, fungi/yeast or parasites, as well as inflammations from chemicals or other toxin exposures. Some of the infectious causes of pneumonia may be spread from person to person. It is cold in the winter so we all huddle together inside, and when someone gets sick it is easy to see how these close quarters increase the spread of infectious diseases, and this is the reason there is an increase of CAP (and influenza) in the winter.

Once CAP is diagnosed, the next step is to determine the appropriate evaluation and treatment. To help inform this decision there are multiple scoring systems to determine the potential severity of illness. These scoring systems take into account the patient’s risk factors, as well as other information from the history (did the patient travel somewhere which would increase the risk of a specific bacteria, have they had their appropriate immunizations, etc.) and physical exam (for example level of blood oxygenation, respiratory rate, blood pressure, heart rate, mental status, and other factors). This helps determine:

Where the patient should be treated; at home, in the hospital or in the intensive care unit.What evaluation is appropriate; for example, empiric treatment without any other tests, a chest x-ray (this may sometimes be falsely negative, such as in a very dehydrated patient that may not ‘show’ their pneumonia on the initial x-ray), blood cultures, sputum cultures, other tests to identify the specific bacteria causing the CAP, and/or other tests. Despite laboratory testing only 30 to 60 percent of patients have a specific cause identified.What treatment is indicated; the type(s) of antibiotics selected, whether they should be administered orally or intravenously, and whether other medications, for example steroid medications, are also indicated.

CAP can be a severe illness, with overall mortality ranging from 5 to 15 percent. Those patients with milder initial disease, specifically those who are determined to be able to be treated at home with oral antibiotics and who do not need extensive testing, usually have a very favorable prognosis, but those who are initially very ill and who require ICU admission have a much more concerning prognosis with as many as a third of these patients dying of their illness.

There are vaccinations that can help reduce risk, so get your flu shot, and speak to your healthcare provider to see if the pneumonia shot (to prevent pneumococcal pneumonia) is recommended for you!